1. Field
The following description relates to disk drives, and additionally, to disk drives configured to reduce noise of a specific frequency band generated when a disk rotates, and methods of reducing noise by using the disk drives.
2. Description of the Related Art
The term disk drive may refer to an optical device using an optical pickup to read or write data to a storage medium. For example, the term disk drive may include an optical device that uses an optical pickup to read or write data to a storage medium. Examples of storage mediums are a compact disk having read only memory (CD-ROM), a rewritable compact disk (CD-RW), a digital versatile disk (DVD) and a rewritable digital versatile disk (DVD-RW).
Often, a tray type disk drive, into which a storage medium may be inserted, is used to read or write data to the storage medium. A tray type disk drive that includes a support unit which supports a storage medium is installed in a housing, and the support unit may be ejected from the housing in order to facilitate the insertion and removal of the storage medium.
Tray type disk drives are often installed into personal computers. However, because of the interest in integrating personal computer products with television monitors and liquid crystal displays, such personal computer products have undergone rapid development. Data may be read or written to a storage medium through use of a slim type disk drive. A slim type disk drive is often incorporated into a portable computer such as a notebook computer. A slim type disk drive is a disk drive into which a storage medium may be directly inserted. A slim type disk drive has a narrow space for accommodating a storage medium. If the disk rotates at high speed, the narrow space causes a flow of turbulent air, separation of air flows, and a pressure change at an air flow boundary layer on a surface of a disk, thereby generating noise
Because noise is caused by a pressure change due to an air flow that occurs if a disk rotates, noise reduction methods have been developed. Such noise reduction methods use a change in an air flow in a limited space inside a disk drive.
In an example of a noise reduction method, air flow is changed by selectively changing the shapes and sizes of components installed in a disk drive. For example, an air flow is changed by changing the diameter of an external circumference of a disk accommodation unit of a tray. As another example, an air flow is changed by changing a size of a pickup base. As a further example, an air flow in a disk drive is changed by using a bead shaped cover.
However, because tray type slim disk drives are designed to reduce thickness and weight, and to have a stable structure, the inner size of the disk drive is likewise reduced and limited. As a result, a bead shaped cover generates touch noise by reducing a gap between an upper surface of a disk and a cover, and disk scratch generated when a tray is open and closed. Because of such touch noise, the use of bead shaped cover is not feasible. In addition, if a cover has a bead shape, manufacturing costs may be increased for maintenance of planarization of the cover due to problems with manufacture of the cover.